Application Of Differential Games Theory To Load Frequency Control Of Area Power System With Multi-source Power Generation Units

To deal with the deviations of frequency and tie-line power of interconnected powersystems caused by large scale integration of wind power, this dissertation applies differentialgames theory as theoretical basis for the solution of this problem, establishes linear two-areainterconnected power system model according to the combination of generation units ofHainan Grid, and carries out research to the load frequency control(LFC) of area powersystem with multi-source generation units. The main content of research of this dissertationcan be divided into the following several parts.Firstly, in order to allocate the system generation between different units under themultiple-input-multiple-output control strategy design method, this dissertation extends theresults of optimal tracking control theory(OTCT) to the framework of linear quadraticdifferential games theory. With fully considering differences of interests and operationcharacteristics between generation units in the same area, control strategies under Nashequilibrium used by different kinds of generation units are designed by appropriate selectionsof weighing matrices in objective functions. Simulation results show that comparing with thecontrol strategies designed by OTCT and PI controller respectively, linear quadraticdifferential games tracking control(LQDGTC) not only accomplishes system control targets,but also fully makes use of characteristics of different generation units and balances theinterests of them.Secondly, the participation degree(PD) of generation unit is defined, and the influence ofsetting values of weighing matrices to it is analyzed. The research result shows that the PD ofspecific unit in LFC can be raised by increasing the values of corresponding elements in itsweighing matrix, while other units’ are dropping, which could be beneficial for grid operatorto decide units’ PDs in LFC according to their characteristics, operation conditions andsystem requirement. So comparing to OTCT, LQDGTC provides more degree of freedom incoordination control between generation units.Furthermore, soft-constrained differential games theory is applied to improve therobustness of control strategy based on. The simulation results show that, comparing toLQDGTC, soft-constrained differential games tracking control strategy can reduce thedeviations in system control targets caused by errors in measuring or estimating of wind farmsoutput, and speed up units’ response.Finally, battery energy storage system(BES) is introduced into LFC of power system.Simulation results show that, BES can effectively suppress the deviations and fluctuations of system frequency and tie-line power caused by variations of wind farms output, and improveunits’ operation condition under current LFC method. Moreover, combining with proposedcontrol strategy, the system no longer experience obvious fluctuations of frequency andtie-line power, the control effect is satisfactory.The research of this dissertation is supported by the National Natural Science Foundationof China(51177050) and the National High Technology Research and Development ofChina(2012AA050201).